Mesure d'une perturbation de pression au Trou qui Souffle (Isère)

Lismonde, Baudouin

doi:10.3406/karst.1993.2316

Cited by 5 publications

(4 citation statements)

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“…6b) and by the rapid reverse of the airflow direction (Fig. 6d), agreeing well with theory (Lismonde, 1993). Moreover on both sides of this limit of +2 • C, the airflow velocity increased due to higher temperature gradient between the inside and the outside of the cave.…”

Section: Periods Of Reversing Airflowsupporting

confidence: 76%

Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

2010

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Abstract. The Gouffre des Diablotins is a deep cave system located in the Swiss Prealps. In 1991, the lower entrance zone of the cave was almost free of ice. Nevertheless the ice volume sharply increased in 1994, plugging almost totally the gallery from the lower entrance. The ice cave has also experienced a flood period between 1996 and 2007 and very heterogeneous ice surface morphologies and textures have formed. Continuous cave climate measurements initiated in 2009 showed the predominant role of winter atmospheric air conditions to drive both the efficiency of chimney-effect air circulation and seasonal modifications of the ice mass. The main part of the ice loss is currently due to sublimation in wintertime.

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Section: Periods Of Reversing Airflowsupporting

confidence: 76%

Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

2010

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“…When values for both parameters are similar, an aspirating regime may be assumed; when an inverse relationship is recorded, an expelling phase may be assumed at that given moment (Lismonde 2002). This method has been confirmed by direct measurements of airflow velocity and direction Sone 2005).…”

Section: Ground Surface Temperaturesmentioning

confidence: 91%

Pluriannual thermal behavior of low elevation cold talus slopes in western Switzerland

2010

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Abstract. The internal and reversible mechanism of air circulation (chimney effect) throughout a porous debris accumulation acts as an efficient advective conveyor of heat, which strongly influences its thermal balance during the whole year. Ground temperature monitoring carried out at eight sites located below the timberline in western Switzerland since 1997 indicates the major role played by winter air temperature conditions in the thermal regime of low elevation talus slopes and relict rock glaciers. In contrast, both snow depth and summer air temperatures have far less influence. The temperature monitoring at these sites offers the longest time series world-wide. Borehole temperature monitoring indicates the presence and growth of permafrost at one particular site from 2004–2006, with its consequent thawing again in 2007.

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“…The chimney effect in caves is a well-known concept, described in classical textbooks on speleology [ 6 ] and cave climate [ 16 , 17 ]. The density difference between the outside air and the cave air controls the driving pressure of the chimney effect.…”

Section: A Chimney Effect: Basic Conceptsmentioning

confidence: 99%

How do caves breathe: The airflow patterns in karst underground

Gabrovšek

2023

PLoS ONE

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Caves and their surrounding fracture systems in the vadose zone of karst regions host a unique atmospheric environment. Understanding the airflow patterns in caves is critical to understanding the properties of the subsurface atmosphere and the chemical interactions between air, water, and rock. The most common driver of airflow in caves is the density difference between the subsurface and the outside air, known as the chimney effect. Observations show that seasonal airflow patterns in caves also depend on the geometry of passages. In this work, I present and use a numerical model of a passage embedded and thermally coupled to a rock mass to study the relationship between the airflow pattern and passage geometry. As the outside air enters the subsurface, it approaches thermal equilibrium with the rock mass along a characteristic relaxation length. This determines the temperature and density contrast between the inside and outside air, and the resulting pressure difference, which drives the airflow. In passages with non-uniform outlines and/or cross-sections, the relaxation length may depend on the flow direction, resulting in different airflow velocities in cold and warm periods for the same absolute temperature difference between the massif and the external temperature. In a passage with a V-shaped longitudinal profile, the airflow is triggered by instability which causes the feedback between the relaxation length and airflow velocity. The airflow pattern can also be altered by snow and ice. Heat transfer in the rock and the thermal inertia of the rock also change the relaxation lengths and cause hysteresis in the curve presenting the airflow velocity vs. temperature difference.

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Mesure d'une perturbation de pression au Trou qui Souffle (Isère)

Cited by 5 publications

References 0 publications

Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

Rapid changes of the ice mass configuration in the dynamic Diablotins ice cave – Fribourg Prealps, Switzerland

Pluriannual thermal behavior of low elevation cold talus slopes in western Switzerland

How do caves breathe: The airflow patterns in karst underground

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